This pack of 10 red atoms are often used to represent oxygen atoms and is for extending your existing set or for replacing lost atoms. Each pack contains 10 balls with two holes in each ball at 105 degrees. Each atom is 23 mm diameter.

Why would I need these? Typically these two-hole oxygen atoms are used to represent oxygen in water, alcohols, and ethers.

The Molymod® system is the original, unique, dual-scale system of high quality low-cost molecular models. These enormously popular sets are ideal for students but are also used by scientists all over the world.